United Nations Intergovernmental Panel on Climate Change (the leading Climate Movement institution). They've produced five major "Assessment Reports" on Climate Changed, dubbed FAR through AR5. Unfortunately, they have credibility problems.↑

NASA Goddard Institute for Space Studies, in New York City (oddly enough, handlers of U.S. surface temperature records). For several years GISS blocked the archiving of averaged USHCN temperature data, but I've compiled a collection of all known versions. ↑

NCDC's U.S. Climate Reference Network seeks to solve the data quality problems of the USHCN. It is composed entirely of high-quality, well-sited measurement instruments. Unfortunately, the records are short. The first USCRN stations were installed in 2002. ↑

Urban Heat Island effect (UHI) is the phenomenon of cities having higher average temperatures than the surrounding countryside. It can distort measured surface temperature trends, because as cities grow they can cause rural temperature gauge locations to become urban locations, resulting in a suprious apparent warming trend. See SurfaceStations.org and homogenization. ↑

Sensitivity

“Climate Sensitivity” is a measure of the (in)stability of the Earth's temperatures, most commonly defined as the globally averaged temperature increase to be expected from a doubling of atmospheric carbon dioxide (e.g., an increase from 300 ppmv to 600 ppmv). (See also TCR, ECS & ESS.)The most straightforward way of estimating climate sensitivity is by examining the result of the “experiment” which mankind has performed on the Earth's climate (by raising atmospheric CO2 levels from near 300 ppmv to above 400 ppmv), noting what happened to temperatures, and extrapolating from those observations.Climate sensitivity estimates in the scientific literature vary wildly, but have generally been declining, as discussed on the sealevel.info Resources page. ↑

TCR

Transient Climate Response, a measure of climate sensitivity over a relatively short time frame (e.g., 20 years).It is formally defined to be the effect on the Earth's average global near-surface air temperature after seventy years, of increasing the atmospheric CO2 level by 1% per year (a rate of increase which would double the CO2 level in seventy years). ↑

ECS

Either “Equilibrium Climate Sensitivity” (EqCS) or “Effective Climate Sensitivity” (EfCS), two similar measures of long-term climate sensitivity. (“Long-term” means a few hundred years.) I've seen the ECS-to-TCR ratio variously estimated between 1.25:1 and 2.28:1, with 1.5:1 being typical.AR5 estimates ECS to be between 1.5 & 4.5 °C (central value 3.0°C). Other scientists, like Bates (2015), estimate ECS to be 1.0 °C or less. I think the IPCC's estimate is too high. Over the 21st century, the trend has been toward lower estimates of climate sensitivity. ↑

ESS

Earth System Sensitivity, the estimated extremely long-term climate sensitivity to a doubling of CO2, after the effects of ice sheet changes are fully felt, and deep-ocean temperatures stabilze (i.e., after tens of thousands of years).It is a hypothetical concept, not very relevant to the climate debate, since it hypothesizes an elevated plateau in atmospheric CO2 levels which is far longer than the anthropogenic CO2 spike will persist. ↑

A controversial elder leader of the Climate Movement, retired April 3, 2013 as director of the NYC office of NASA GISS. In 1988, 3½ months before the U.N. created the IPCC, Hansen was lead author of a highly influential paper predicting catastrophic global warming. He and his colleague, Makiko Sato, have a web page about sea-level here. ↑

AMO

Atlantic Multi-decadal Oscillation: a very long-duration oscillatory pattern to North Atlantic weather, with an estimated period of about 60-70 years. (See also PDO, ENSO & MJO.) ↑

PDO

Pacific Decadal Oscillation: a long-duration oscillatory pattern to Pacific weather, especially in the Northern Pacific, with a period of about 15-30 years. (See also AMO, ENSO & MJO.) ↑

Madden-Julian Oscillation is a little-known, short-duration oscillatory pattern to tropical & subtropical weather (roughly ±30° latitude), which can occur several times per season. (See also AMO, PDO & ENSO.) ↑

TOB or TOBS

Time of OBServation, variations of which can bias temperature measurements, which is the rationale for some of the striking “homogenization” adjustments to old temperature records, which have made the past reportedly colder and the present warmer, bolstering the apparent case for GW. ↑

Homogenization

Adjustments of temperature data to hopefully correct errors and biases (“inhomogenities”) caused by station moves, instrument changes, TOBS, UHI, etc. The details of those adjustments can have a dramatic effect on reported temperature trends. ↑

Model

A “computer model” (or just “model”) is a computer program which simulates (“models”) real processes for the purpose of predicting their progression. The utility and skillfulness of models is dependent on how well the processes which they model are understood, how faithfully those processes are simulated in the computer code, and whether the results can be repeatedly tested so that the models can be refined.Specialized models, which try to model reasonably well-understood processes, like PGR and radiation transport, are useful, because the processes they model are manageably simple and well-understood. Weather forecasting models are also useful, even though the processes they model are very complex, because the models' short-term predictions can be repeatedly tested, allowing the models to be validated and refined.But more ambitious models, like GCMs, which attempt to simulate the combined effects of many poorly-understood processes, over time periods too long to allow repeated testing and refinement, are of dubious utility. (Worst of all are so-called “semi-empirical models,” which aren't actually models at all.) ↑

GCM

General Circulation Model, a large, complex computer program which attempts to simulate ("model") the Earth's climate. ↑

Semi-empirical

So-called “semi-empirical modeling” is an oxymoron: “modeling” that doesn't actually model anything. It is similar to modeling, but without reference to any physical basis. It is really just curve-matching. It can be made to produce just about any desired result.GCMs are subject to criticisms that they don't accurately model the real world, because of inconsistency with observations of things like clouds and the predicted tropical mid-tropospheric hot spot. Semi-empirical modelers neatly avoid such criticism, by not even trying to model the real world. It's the worst sort of junk science. ↑

Post-Glacial Rebound, isostatic movement of the earth's crust due to the last major deglaciation (circa 10,000 years ago); it causes falling sea-levels in Scandinavia, around Hudson Bay, and elsewhere. ↑

An English leader of the Climate Movement, who infamously called the untimely death of John Daly "cheering news." ↑

Climategate

The “Climategate” scandal was the result of a pair of “document dumps” in 2009 and 2011, by a still-anonymous whistle-blower calling himself “FOIA,” of climate-related emails, documents & computer code, which showed that leading Climate Movement scientists had been manipulating & withholding data, hiding evidence, flouting FoIA laws, and blackballing skeptics, to promote CAGW.Phil Jones' email to Michael Mann about the "cheering news" of John Daly's death was one of those released. (See also Fakegate.) ↑

University of East Anglia's Climate Research Unit, source of the Climategate files. ↑

CWP

The Current Warm Period, Present Warm Period (PWP), Modern Climate Optimum, or simply Modern Optimum (MO), circa 1900 A.D. to present. Preceded by the LIA. Similar to the MWP, RWP & BAWP. ↑

LIA

Little Ice Age, circa 1350-1850 A.D., when temperatures were much colder than they are now. Preceded by the MWP, and followed by the CWP. ↑

MWP

Medieval Warm Period (a/k/a Medieval Climate Optimum), circa 850 to 1300 A.D., when temperatures were probably about as warm as they are now. Preceded by the DACP, and followed by the LIA. (See also RWP, BAWP & HCO.) ↑

DACP

Dark Ages Cold Period, circa 400 to 800 A.D., when temperatures were significantly colder than they are now. Preceded by the RWP, and followed by the MWP. ↑

RWP

Roman Warm Period, circa 250 B.C. to 350 A.D., when temperatures were probably at least as warm as they are now. Preceded by the Iron Age Cold Period, and followed by the DACP. (See also MWP, BAWP & HCO.) ↑

IACP

The “Iron Age Cold Period,” (a/k/a Iron Age Cold Epoch, or Iron Age Neoglacial), circa 1200 B.C. to 300 B.C., was an extended cold period, preceeded by the BAWP and followed by the RWP. See also LIA & DACP.) ↑

Minoan Warm Period

The Bronze Age Warm Period (BAWP) or Minoan Warm Period, roughly circa 1450 B.C. to 1200 B.C., was a period when temperatures were apparently at least as warm as they are now. It was followed by the long IACP. (See also HCO, RWP & MWP.) ↑

Holocene Climate Optimum

The Mid-Holocene Warm Period, Holocene Climatic Optimum, Altithermal, Hypsithermal, or Holocene Climate Optimum (HCO), was an extended period from about 7,000 B.C. to about 3,000 B.C. when temperatures were apparently warmer than present (at least most of the time). (See also BAWP, RWP & MWP.) ↑

Holocene

The Holocene is the current interglacial (warm) period, which began circa 10,000 B.C., and has lasted about 12,000 years, so far. It was preceded by the last glacial period. The previous interglacial was the Eeman. ↑

Last glacial period

The last glacial period was the most recent period when ice sheets covered most of northern North America and northern Europe, and sea-levels were much lower than present. It is considered to have begun circa 113,000 B.C., and ended circa 10,000 B.C., with maximum ice sheet extent (“LGM”) circa 25,000 to 18,000 B.C. It was preceded by the Eemian interglacial, and followed by the Holocene. ↑

The Eemian was the interglacial (warm) period before the last glacial period. It lasted about 15,000 years. It began circa 128,000 B.C., ended roughly 113,000 B.C., and was followed by the last glacial period, and then by the Holocene. ↑

BP

“BP” is, literally, an abbreviation for “before present,” but that's usually not what it actually means. Due to an obscure and unfortunate convention of the paleoclimate community, “BP” usually means “before 1950 A.D.” See also “ka.” ↑

ka

“ka” is an abbreviation for “kilo annum,” literally meaning “thousand(s) (of) years before present.” It is slightly ambiguous, because it can mean either before the current date, or before 1950. See also “BP” and “Ma.”” ↑

Ma

“Ma” is an abbreviation for “mega annum,” meaning “million(s) (of) years before present.” See also “ka.”” ↑

The “solar constant” is the total solar irradiance at top of atmosphere, where the Earth directly faces the Sun, when the Earth is one AU from the Sun. Estimates of its value, from about thirty five years of satellite measurements, are in the range of 1360 to 1370 W/m². Just how “constant” the Solar Constant really is is disputed. (The average irradiance over the entire Earth is 1/4 of that, i.e. about 341±1.25 W/m², because the surface area of a sphere is 4× the area of a circle of same radius.) ↑

RCP

“Representative Concentration Pathways” are what the IPCC calls their four climate model scenarios: RCP2.6, RCP4.5, RCP6 & RCP8.5, with the number representing the size of the expected net radiative forcing in year 2100, in W/m2 (2.6 W/m2 to 8.5 W/m2). Those radiative forcing numbers are relative to the year 1750 (during the Little Ice Age), and they assume large net positive (amplifying) feedbacks and resultant high climate sensitivity, for which there is scant evidence. ↑

The Ice, Cloud,and land Elevation Satellite was a NASA satellite mission, which measured surface topagraphy via laser altimetry (Lidar). It failed prematurely, due to a design defect. ICESat-2 is a planned follow-up mission. ↑

CryoSat

CryoSat-2 is a European Space Agency satellite mission which measures polar ice caps with radar altimetry. (The predecessor CryoSat-1 satellite was lost in a launch failure.) ↑

Mann, Michael

A leading U.S. Climate Movement scientist, who, with coauthors Raymond Bradley & Malcolm Hughes, famously created a (since discredited) "hockey-stick" shaped graph of paleo-temperature data from tree-ring proxies, which appeared to erase the MWP & LIA from history. ↑

Muller, Richard

A leading U.S. Climate Movement scientist, who was critical of Michael Mann after the Climategate revelations. ↑

Thermohaline Circulation or Meridional Overturning Circulation (MOC) refers to the “Atlantic Conveyor” (AMOC) and related currents which carry warm surface water from the tropics toward the poles (most famously via the Gulf Stream), and currents deep in the ocean which carry cold water back toward the tropics. ↑

Cloud Radiative Effect (CRE) refers to the varying effects of clouds on incoming/downwelling and outgoing/upwelling radiation to/from the earth's surface. At night clouds have a warming effect, but in daytime clouds shade & cool the surface. The net effect is complex and poorly understood. ↑

Greenhouse Gas: any trace gas (such as CO2, CH4 or water vapor) which could help warm the Earth's surface by blocking IR emissions into space. (Note: the term is a misnomer, because that's not how greenhouses work.) ↑

Carbon dioxide, the most important non-condensing greenhouse gas, the “precious air-fertilizer” (SciAm), a colorless, odorless trace gas, formerly called “carbonic-acid gas,” the raw material for plant growth, the bubbles in soda pop, the stuff you exhale. ↑

“CO2e” or “CO2 equivalent” (not to be confused with eCO2) is an attempt to roughly approximate the combined warming effect of all anthropogenic GHGs, by adding to CO2 concentration a weighted sum of the concentrations of other anthropogenic GHGs. Here's an example of one such weighting formula. ↑

eCO2

“eCO2” is an abbreviation for “elevated CO2” (not to be confused with CO2e). ↑